<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <!-- 
        转换布尔类型
        Boolean();  强制转换
        0、''、null、undefined、 NaN  输出的是false
        其余的输出的是true
     -->
    <script>
        console.log(Boolean(123));        //  true 
        console.log(Boolean('abc'));      //  true 
        console.log(Boolean(null));       //  false
        console.log(Boolean(undefined));  //  false
        console.log(Boolean(0));          //  false
        console.log(Boolean(''));         //  false
        console.log(Boolean(NaN));        //  false
        console.log(Boolean(1));          //  true
    </script>
</body>
</html>